Study of the Healing Mechanism of SAPs by an Optimized Water Permeability Test
YANG Haitao1,2,3, LIU Juanhong1,2,3, JI Hongguang1,2,3, ZHOU Yucheng1,2,3
1 College of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China; 2 Beijing Key Laboratory of Urban Underground Space Engineering, University of Science and Technology Beijing, Beijing 100083, China; 3 State Key Laboratory of High-efficient Mining and Safety of Metal Mines of Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China
Abstract: The concrete is susceptible to cracking due to its high brittleness. This leads to the serious leakage of water which is harmful to the safety of life and property. Self-healing concrete containing superabsorbent polymers (SAPs) is an ideal material with crack self-repairing ability and can improve the durability of concrete structure. The SAPs are cross-linked hydrogel network and will absorb solution up to several hundred times of their own weight. As a new admixture, SAPs can improve the self-healing capacity, freeze-thaw resistance and mitigate the autogenous shrin-kage of concrete. In this paper, the distribution and flow rate of water in a crack with non-equal width were studied for the first time. Moreover, the effects of particle size of SAPs and crack width on the healing efficiency (Ψ′) of SAPs were also investigated by an optimized water permeabi-lity test. The self-healing mechanism of SAPs was analyzed based on the morphology of SAPs in a crack. The results show that the water in a crack with non-equal width is unsaturated when the water head (I) is small, resulting in the underestimation of the Ψ′ value. The increase of I va-lue can help to raise the saturation degree of water in the crack with non-equal width and improve the accuracy of the Ψ′ value. In addition, the absorption capacity (α) of SAPs during the mixing procedure and the crack width have significant impacts on the Ψ′ value. The SAPs with M and L particle sizes have a large α value and can seal or partly seal the crack which is within the original void. While SAPs with S particle size have a small α value and can hardly seal the crack effectively.
杨海涛, 刘娟红, 纪洪广, 周昱程. 利用优化的水渗透试验研究SAPs的裂缝愈合机理[J]. 材料导报, 2020, 34(8): 8188-8193.
YANG Haitao, LIU Juanhong, JI Hongguang, ZHOU Yucheng. Study of the Healing Mechanism of SAPs by an Optimized Water Permeability Test. Materials Reports, 2020, 34(8): 8188-8193.
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